Russia has ordered the expulsion of an alleged American CIA agent working undercover at the US embassy who was discovered with a large stash of money trying to recruit a Russian agent.
Russia's Federal Security Service (FSB, ex-KGB) identified the man as Ryan C. Fogle — third secretary of the political section of Washington's embassy in Moscow — and said he had been handed back to the embassy after his detention.
The foreign ministry said it was summoning US ambassador Michael McFaul for an explanation and slammed Washington for what it described as "provocative acts in the spirit of the Cold War".
It declared Fogle to be persona non grata who had to return to the United States "as soon as possible" — a complete contrast to the joint pledges for intelligence cooperation after the Boston bombings.
Photographs published by state English language television RT showed a baseball-capped Fogle being pinned face down to the ground and having his hands put behind his back for the arrest.
He was then shown being questioned at the Federal Security Service while documents such as his passport and a stack of 500 euro notes along with some letters were displayed.
The FSB footage also displayed supposed espionage equipment including two wigs, a compass, an atlas of Moscow and a somewhat old-fashioned mobile phone.
The FSB warned in a statement that "recently, the US intelligence service has made repeated attempts to recruit the staff of Russian law enforcement agencies and special services".
Russian state television shown footage provided by the FSB in which Fogle is seen sitting down in a checked shirt as a man — presumably a Russian security officer — tells the suspect about his alleged crime.
He is then accused of offering $100,000 for espionage to a security service employee who is involved in counterinsurgency work in the Russian North Caucasus.
"We did not believe this at first, because as you know the FSB has been actively helping the investigation of the Boston blasts," the officer says as Fogle and three men silently listen with arms crossed.
The incident comes amid a new downturn in Russian-US relations sparked by the Syrian crisis and concern in Washington over what it sees as President Vladimir Putin's crackdown on all dissent.
The last major spy row between the two former Cold War rivals involved the glamourous Anna Chapman and large group of Russian spies who were arrested on the US East Coast in June 2010.
That spy scandal — which ended with their swap for four Russians convicted of spying for the West — was a huge embarrassment for Russia's foreign intelligence at the time.
The FSB and Russia's tightly-controlled state media appeared intent on showing to the public that the man it had caught was a real agent who posed a danger to Russia's interests.
The photos published by RT also showed a document entitled "printed instructions for the Russian citizen being recruited".
Parts of the recruiting document allegedly used by Fogle read: "Dear Friend. This is an advance from somebody who is impressed with your professionalism, and who would value highly your future cooperation with us".
As well as $100,000 outright "we offer up to $1 million per year for long-term cooperation, with a promise for an additional bonus for information that will help us".
Analysts said the fact that the case received such media attention means that senior Russian leaders had decided to use the arrest to make a political point to Washington.
Some such cases are often handled quietly and tit-for-tat expulsions are sometimes only made public once completed.
Independent analyst Alexander Golts added that the million dollars the United States was allegedly willing to pay the Russian security service worker seemed far too large for a regular worker.
"These numbers raise red flags," Golts said in a telephone interview. "For that amount, they could have expected to at least get the deputy head of Russia's foreign intelligence."